Right! So, now that all the bone-brittle non-milks have left, let's rap about milk. By now, we should all know that skim milk is just a carton/jug/bag of bullshit meant to assuage the cholesterol concerns of baby boomer parents who wanted to raise their children to have strong skeletons without all the collateral artery damage. Skimming the fat off of perfectly delicious milk doesn't turn it into magical protein juice. In fact, as NPR pointed out a year ago, low-fat milk was associated with more weight gain over time than fattier whole milk.
Now, NPR is back with a new report that further confirms how whole dairy products (milk, yogurt, butter) are more often the choice of skinnier people all over the world. Swedish researchers found out recently that middle-aged men who consumed high-fat milk and butter were less likely to become obese over a period of 12 years than men who rarely consumed high-fat dairy. Meanwhile, in another part of Europe, a second study found that research warning about the fattening effects of whole milk and other full-fat dairy products were inconclusive. In fact, some of those studies even found the exact opposite thing to be true — full-fat dairy makes people thin. Or thinner. Maybe.
There are three possible explanations for this counterintuitive finding that higher fat dairy products create less fat humans. The first is pretty simple, so simple you'll no doubt smack your forehead at your own inability to guess it. High-fat dairy fills us up faster, so we consume less food as a result of all that rich, yellow milk sloshing around in our tummies ("tummy" is the scientific word for "stomach"). The second explanation is a little more eldritch — there are "bioactive substances" creeping and crawling around in our guts. Those substances are "activated" like sleeper Soviet spies when a tide of whole milk washes over them, and their activation helps kick our metabolism into a higher gear. This gif should adequately illustrate the phenomenon:
The third explanation is even stranger: whole milk coats all of our internal organs in a slick, oily sheen that helps food just slide right through without getting stuck. This is commonly referred to as the "luge effect" — instead of getting lodged in your intestines and turning into fat (which is how fat accumulates, just FYI), the luge effect ensures that all those excess meat bits and pizza flavored Combos just slide right through with the ease of a Sochi Olympian.
Don't think about it too much — it's science.